Apr 28 2014
Orogeny refers to the cumulative effect of forces and events that result in a large structural deformation of the Earth’s crust. This structural deformation occurs due to the engagement of tectonic plates. As a result of these engagements, long tracts of deformed rocks are formed; these are called orogens, or orogenic belts. Orogeny is a Greek word meaning mountain origin. Orogeny is the primary mechanism for the formation of mountains.
After orogeny, the mountain belts are formed with shallow-water sedimentary rocks on the inner side of the mountain belt, and deep-water sedimentary rocks in the heart of the mountain belt. There are thick accumulations of sandstone and conglomerate accumulates as the mountain ranges erode. As a result of orogeny, folding and thrust faulting of the earth’s crust occurs. The collective processes that lead to mountain formation are called orogenesis.
Mountain Formation
The formation of orogen is the result of a tectonic process called subduction. Subduction occurs when a continent rides forcefully upon an oceanic plate. The orogenic plates that are formed are usually long, and are in the form of parallel strips of rock that exhibit similar characteristics along the length of the belt. An orogeny results in the formation of an orogenic system, or a foredeep-foreland system.
Foredeep is the subsistence zone, and foreland is the zone that lays ahead of the foredeep. Similar to any geologic structure, orogenic systems also go through the magmatization, metamorphism, crust thickening, and crust melting stages. An anorogenic system undergoes erosion, which removes most of the mountains.
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